Signors to said bartlett and oliver h



No. 6|4,36I. Patented Nov. I5, |898. E. 0. BARTLETT & C. V. PETRAEUS. METHOD DF AND APPARATUS FDR PURIFYING AND SAVING THE FUMES 0F LEAD.

(Application mad Jia@ 21, 1893.)

No Model.)

. mi w wUNITED VSTATES PATENT Erich,

AYRE O. BARTLETT AND CARL V. PETRAEUS, OF JOPLlN, MISSOURI, ASL SIGNORS TO SAID BARTLETT AND OLIVER I-I. PIOIIER, OF SAME PLACE;

METHOD 0F AND APPARATUS FOR PURIFY'iNG AND AvlNG FUMES '0F LEAD.

SPECIFICATION forming part or Letters :Patent No. 614,361, dated November 15, 1898.

Application filed .Tune 2l, 1893. Serial No. 478,824. (No model.)

.To @ZZ whom it may concern:

Be it known that we, EAYRE O. BARTLETT and CARL V. PETRAEUs,citizens of the United States, residing at Joplin, in the county of Jasper, in the State of Missouri, haveinvented a certain new and Improved Method of and Apparatus for Purifying and Saving the Fumes of Lead Driven Off from Metallurgical Furnaces, of which the following is a true and exact description, reference being had to the accompanying drawings, which form a part thereof.

Our invention relates to the purification of lead fume driven off from metallurgical furnaces of various kinds and the separation and saving of the same for use as a pigment.

Heretofore lead fume driven off from metallurgical furnaces has been separated from the gaseous constituents of the furnace-smoke in various ways, the most successful being by iirst causing the furnace smoke to pass through a system of cooling-dues and then separating it from the gases by means of fabric screens. ,The fume, however, as first formed is untted for use as a pigment, because it is largely mixed with unconsumed carbon and also because the fume arising from the generality of metallurgical furnaces is largely in the form of lead sulfid and of a dark color, and it has therefore been found necessary to subject the fume to some process of reburning for the purpose of eliminating the carbon mixed with it and also of oxidizing the lead suliid toalead sulfate. Many devices have been tried with varying degrees of success for so purifying the fume, and, among other methods, the fume has been subj ected to the action of another fire as it passes from its point of generation to the screen system; but while this plan is reasonably successful in whitening and purifying the fume it has been found objectionable, owing to the fact that the smoke ordinarily contains a large quantity of sulfur dioXid, which, under the high temperature and other conditions of treatment in the second furnace, unites with the oxygen and moisture present to form sulfuric acid, which rapidly destroys the fabric of the screens. Owing to this drawback the approved practice has been to first separate the dark-colored fume, permittingthe escape of the sulfurous acid, and then effect its purication by subsequent treatment.

The object of our invention is to enable us to use the old method of reburning in transit and to eliminate the sulfuric acid formed before the purified smoke reaches the fabric screens; and our process, broadly speaking, consists in generating the fume-containing smoke, passing it through or over a second 6o furnace to purify and whiten the lead fume. then passing it through a cooling system to reduce the temperature of the smoke to, say, from 200o to 300 Fahrenheit, then bringing it into contact with water to absorb and eliminate the sulfuric acid, and then screening the purified residue, preferably reheating the smoke after subjecting it to the action of the water, so as to prevent the presence of moisture in sensible form in the screen.

Reference is now had to the drawings which illustrate our invention, and in which- Figure l is a plan view of an apparatus adapted for use with our improved process and embodying the novel features which we desire to protect; Aand Fig. 2 is a side elevation of the same, taken on the line a: of Fig. 1.

A indicates the fume-generating furnace, which may be of various constructions, that 8o illustrated being that familiarly known as a Scotch eye furnace, A indicating the stack of the furnace, which is provided with a damper a', and Aga flue leading therefrom to a sccond furnace, (indicated at B.) This furnace is preferably of the reverberatory form shown and is heated by a gas-dame issuing from the opening C. The smoke of the furnace A, passing into the said reverberatory furnace B, is subjected to the action of a high heat 9o and in the presence of sufficient oxygen to secure the combustion of the unconsumed carbon and the oxidation of the sulfid of lead to lead sulfate. From the furnace B the smoke passes first to a dust-chamber D, in which ponderable particles settle in the form of flue dust, the lighter fume passing with the gases into the cooling-flue E, which said flue is preferably made up largely of what are familiarly known as goosenecks or U- roo shaped tubes, as shown in the drawings. The smoke is drawn through the cooling-flue and forced into the flues and chambers following it by means of an exhaust-fan, as indicated at F, and having been cooled to a sufficient degree it passes through the water-tower G, which may be a device of any kind adapted to bring the smoke into intimate contact with water, but not to force it through a body of water. In the construction shown the tower Gr, which forms a part of the flue, is filled up with boards set on edge and at a little distance from each other, each layer of boards being set in the opposite direction to those above and below it, or the filling of the tower could be of any material which will provide a series of intercommunicating interstices through whichthe water can flow down and the smoke pass up. Water is introduced by the top of the tower through apipe I-I, preferably provided with a regulating-cock h and a sprinkling-head H. As the smoke passes up through the tower it is brought into very intimate contact with the spray and thin lms of Water passing down through the same, and the mineral acid contained in the smoke is wholly or to a large extent absorbed by the water and elimina-ted from the smoke. Some particles of the lead fume will also be carried down by the water which iiows out from the bottom Gr3 of the tower to a conduit G4, and can be carried thence to a settling-place, (not shown,) from which the particles can be recovered. From the top of the towerthe smoke passes through the screen system. Preferably, however, we provide means for reheating the smoke before screening it, which eX- tend along the iiue E and communicate with the chamber K, which is built around a portion of the cooling-flue, preferably the hottest portion thereof. From the chamber K we carry the smoke through the fine L to the screen system. The iueL is shown communicating with a hopper M, which in turn connects with a series of fabric bags N N, the., contained in a bag-house O.

In another application filed by us on'the 21st day of June, 1893, and bearing the Serial No. 478,323, we have shown and described a combination of a furnace with the cooling system, water tower, reheating apparatus, and screen system substantially the same as hereinabove described, and in said applica tion we have claimed, broadly, both the process and apparatus, our present invention relating solely to the construction and method in which a second furnace is provided for the purpose of reburning or purifying the fume as the smoke passes from the furnace in which it is generated to the screen system.

Having now described our invention, what we claim as new, and desire to secure by Letters Patent, is-

1. The method of purifying fumes of lead driven o from metallurgical furnaces and separating the same from furnace-gases which consists in generating the fume, then causing the smoke from the generating-furnace to pass through or over a second furnace to eliminate combustible ingredients and whiten the lead fume, then cooling down the purified smoke, then causing it to pass in intimate contact with but not through Water to eliminate mineral acid and then screening the residue.

2. The method of purifying fumes of lead driven off from metallurgical furnaces and separating the same from furnace-gases which consists in generating the fume, then causing the smoke from the generating-furnace to pass through or over a second furnace to eliminate combustibleingredients and whiten the lead fume, then cooling down the purified smoke, then causing it to pass in intimate contact with but not through water to elimi nate mineral acid, then reheating the smoke and then screening the residue.

3. The combination of a fume-generating furnaceA with a second smoke-purifyin g furnace B, a coolingflue leading therefrom, means for bringing the smoke into intimate contact with water, said means situated in or forming a part of said iiue, a flue J, K, L, leading therefrom and inclosing a part of the cooling-flue aforesaid, a screen system and means for conducting the smoke thereto.

EAYRE O. BARTLETT. CARL V. PETRAEUS.

Vitnesses:

A. E. SPENCER, R. O. MCCONNELL. 

